Method of making protein food product



United vStates Patent METHOD OF MAKING PROTEIN FOOD PRODUCT Mortimer Louis Anson, New York, N. Y., and Morton Pader, West Englewood, N. J., assignors to Lever Brothers Company, New York, N. Y., a corporation of Maine a No Drawing. Application June 3, 195

Serial No. 434,313

3 Claims c1.99-14 This application is a continuation-in-part of 'our copending application Serial No. 304,844, filed August 16, 1952.

This invention relates to a method of making protein food products which resemble the texture, general appearance and other properties of meat or meat products.

A process for making such food products from animal or vegetable proteins, which are capable of being made into filaments, has been proposed in British Patent No. 699,692 which includes the steps ofextruding an alkaline solution or dispersion of the protein through fine orifices into a coagulating bath, usually an acid/salt solution, and applying to the filaments an edible substance which serves to hold' the filaments in position in the product. a e

It has now been found that the above-mentioned meat-- like properties may be more closely simulated by converting the filaments termed in .the coagulating bath at least partly to a chewy protein gel. I

The conversion to a chewy protein gel involves the adjustment of the pH of the protein filaments, which may, but need not, have been stretched, to a value conduc ive to gel formation on being heated and the subsequent application of sutficient heat to form a chewy protein 'gel. The term gel precursor willbe used henceforth to refer to protein filaments in a condition in which at least part of the protein is capable of forming a chewy protein gel on being heated. i V v The process of the invention is particularlysuitable for making food products which simulate not only the texture and chewiness of various kinds of cooked meat or meat products but also their moistness. The process allows products to be made which also simulatethe color, general appearance and taste of a variety of kinds, of

cooked meat or meat products. 1

Usually, the product also contains substances other than protein filaments, such as dyes, flavoring materials, fat, starch or flour which maybe inc'orporatedin order to impart color, flavor or a desired texture to theproduct. Such additives may be incorporated at one or more stages of the process. Thus, ,in brief outline, ,a typical process maycomprise the following steps: the. preparation of the;filaments;- the treatment of the filaments with an alkaline agent to convert them to gel precursors; the admixture of additives, for example by passing the gel precursorgthtrou'gh a bath'containing the'desired additives in the form .ofaliquid; ,the removal of excess liquid from the mixture of gel precursors and additives, for instanceby squeezing; the shaping of ther'esultant mixture to the shape desired of the product,,for example by packing into a canyand the application of heat to the mixture in an autoclave. w a

' In the preparation of protein filaments for use according to the present invention any protein-solutions used in the art, for the purpose may. beemployed. Examples of suitable proteins are peanut protein, soy protein and casein.

Solutions prepared according to the methods I described in copending application Serial No. 357,916, filed May- 27, 1953, by Edward Green, Robert W. Graham, Howard S. Gardner and Alan W. Holmes, en-

titled Improvements in the Preparation of Protein Solu-.

tions, are particularly suitable. Similarly, any, solution capable of coagulating the extruded streamlets of protein may be used, provided it is compatible with the subse-. 1

quent use of the filaments in food'products. An aqueous solution at or near room temperature containing sodium chloride and acetic-acid is very suitable, about.12% by weight of sodium chloride and about 2% by weight ofacetic acid being preferred. The concentrations of electrolyte may, however, vary between wide limits.

The filaments may be converted to gel precursors on emergence from the coagulating bath, but it is usual to interpose one or more steps of treatment after emergence;

from the coagulating bath and before the conversion to gel precursors. in a hot electrolyte solution. Stretching of the filaments,

instance, be used in the strengthening treatment.

or near-room temperature.

The pH of the filaments emerging from the coagulating solution is generally below the isoelectric point of the,, protein. Any subsequent treatment, such as the cooling treatment just described, may raise the pH of the fila ments to a limited extent, but notusually to the extent necessary to convert the filaments to gel" precursors. The conversion may be elfected by treating the filaments with an alkaline agent, such as by immersion in an aqueous solution of sodium hydroxide, carbonate or bicarbonate or like compounds. adjusting the pH of the filaments is that described in copending application SerialNo. 408,029, filed February 3,. 1954, by James D. Devey, Gordon Kellam and Alan 1.;

MacFarlane, entitled Improvements in the Manufacture of Protein Filaments. I

The pH range to whichthe filaments are adjusted t0.; convert them into gel precursors may vary with the-na-. ture of the protein.

to ensure that at least some gelformation takes place when the filaments are heated in an autoclave but it- The pH should be sutficiently high should not be high enough-to cause the filaments toldisintegrate before being heated or to cause them to lose all filamentary character on being heated in an autoclave. There has been observed an increase in the tendency of certain samples of protein towards the development of,

undesirable color in the gel ultimatelyobtained as the' pH of the gel precursor is raised and too high a pH value may also lead to a certain rubberiness of the gel. The

pH is usually adjusted to a value of atv least about 6.0,. normallybetween about 6.5 and 7.5. The range between: It is thought that a pH gradient 6.5 and 7.0 is preferred. exists inside the gel precursor, the pH increasing from the outside to the inside of the filaments, as a result of which the tendency of the protein to lose its filamentary. charac-;

ter upon being heated in an autoclave is reduced. The pH values quoted are average values determined by squeezing a small portion of filaments to remove surplus liquid, immersing'the portion in 5 times its weight'of distilled water, stirring so as to cause the disintegration of the filaments, allowing the mixture to stand for 5 min-. utes and then determining the pH of the mixture With-a filament which will tend to gel. Thus, the value to which Patented 'May 6, 1958.

Thus, thefilaments'may be strengthened A suitable method for the pH of the filaments is adjusted may he used to control the texture of the final product.

Additives may also be used to control the texture of the product. They may serve as anti-fusion agents which reduce the-tendency ofthe protein to lose its filamentary character on being heated in-an autoclave, so that the pH of the filaments may, if desired, be raised above the usual ranges or so that the filamentary character of the product mayberetainecl to an increased extent. Coating the filaments with, for instance, a suspension of wheat flour has this effect.

Theheating-iscarried out for a time sufiicient to convert the gel precursor to a protein gel. It is preferred to heat the precursor to at least the boiling point of water. This may be doneconveniently by subjecting the precursor to steam at super-atmospheric pressure in an autoclave: Heating for about 1 hour at a temperature of about 115. C. with steam at a pressure in the range of to p. s. i. g. has been found to be asatisfactory' procedure. l

Additives may be incorporated ina food product according to the invention by adding them to the solution, to be extruded,'when they will be contained in'the filaments, by mixing them with the filaments before the latter are converted to gel precursors, by mixing them with the gel precursors before their conversion to gels or by mixingthem with the gelled filaments. It is permissible, and often convenient or d'esirable", to add one or more additives at one stage and more of the same additive or additives or othcrsat ditferent'stages of manufacture. It will be clear, of course, that additives mixed With or incorporated in the filaments before their conversion to gels must be of such a mature or of such proportion as not to interfere with the desiredgel formation and all additives must, of course, be compatible with the use of the} product as a food product. p

The purpose of the additives may be to impart color, flavor ora desired textureto the product. Among such additives there may be mentioned dyes, flavoringmaterials, fan-starch, flour, and gums. Other additives such as amino-acids or vitaminsmay serve to improve the nutritional value of the product. Sometimes, an additive or mixture of additives is required to hold the filaments in position in the product.

The length of the filaments in the product will vary with the nature of the product. To make a product simulating a piece of meat, such as roast beef or harm, bundles of filament gel precursors or of gelled filaments maybe cut into lengths corresponding to the length of the cursors to gelled filaments of the required size, thoroughly mixing thechopped pieces withwhatever additives it is desired to add at this stage, shaping the resultant mixture to the desired form and, if required, heating the assembly either before or after packaging. Sausage type products may be made by filling sausage casings with the mixture of chopped pieces and additives.

EXAMPLE 1 Extraction and separation of protein for filaments A commercial, substantially skin-free, oil-free, low temperature solvent-extracted peanut meal was extracted at pH 7.5 withanaqueous sodium hydroxide solution (1 part meal, 9 parts of 0.03% sodium hydroxide solution). The insoluble residue was removed by centrifiuging and the protein was then precipitated from the solution at pH 5.0 by the addition of 10 N hydrochloric acid. The precipitated protein was separated by centrifuging.

Preparation of filaments The precipitated protein suspension so obtained was dissolved in aqueous sodium hydroxide and the pH of the solution was adjused to about pH 12.3 by a further addition of sodium hydroxide at which pH the solution was aged for about ten minutes. then reduced to about pH 10.8 by the addition of 2 N acetic acid. the protein may, if desired, be added to the solution.) The resultant alkaline solution containing about 19% by weight of protein solids was extruded through a battery of six spinnerets (having holes microns in diameter) into a coagulating bath maintained at room temperature which comprised an aqueous solution containing 12% by weight sodium chloride and 2% by weight acetic acid.

Intermediate treatment of filaments The bundles of filaments formed in the coagulating bath were amalgamated into one tow which was guided from the coagulating bath into a strengthening lbath comprising a solution. similar to that of the coagulating bath but maintained at 60 C. Duringthe strengthening treatment, which was of about 2 minutes duration, the filaments were stretched to double their initial length. The tow was then guided to another 'bath comprising an aqueous solution containing 5% by weight sodium chloride and maintained at 20 C. and then through squeeze rollers.

. Further processing The pH of the filaments was raised to 6.8 by immersion in a buffer solution containing disodium hydrogen orthophosphate and citric acid. The filaments were then passed through squeeze rollersto remove excess solution. The filaments were cut into lengths corresponding to the height of the can-into which they were to be packed and i were then tightly packed'into the can in such a way that After cooling the contents were removed from the cans and were chopped up into pieces. These pieces can be served in gravy as a stew-like product or the pieces and gravycan be'mixedand the mixture canned.

We claim:

1. In the preparation of a protein food product, the steps which comprise adjusting the pH of protein filaments to within the range of 6 to 7.5 and then heating the filaments at a temperature of at least C. to convert them into chewy protein gel.

2. Inthepreparation of a protein food'product, the steps which comprise extruding a plurality of protein filaments into a coagulating bath, adjusting the pH of the filament to within the range of 6 to 7.5, and then heating the filaments at a temperature ofat least 100 C. to convert them into chewy protein gel.

3. A method according to claim 2 in which the protein filaments are heated by autoelaving with steam at a temperature of at least 100 C; a 1

References Cited in the file of this patent UNITED STATES PATENTS 670,283 Kellogg Mar. 19, 1901 869,371 Kellogg Oct. 29, 1907 2,560,621 Wrenshall July 17, 1951 2,682,466 Boyer June 29, 1954 2,730,448 Boyer Ian. 10, 1956 FOREIGN PATENTS 699,692 Great Britain Nov. 11, 1953 The pH of the solution was (An' edible dye which will combine with 

1. IN THE PREPARATION OF A PROTEIN FOOD PRODUCT, THE STEPS WHICH COMPRISE ADJUSTING THE PH OF PROTEIN FILAMENTS TO WITHIN THE RANGE OF 6 TO 7.5 AND THEN HEATING THE FILAMENTS AT A TEMPERATURE OF AT LEAST 100*C. TO CONVERT THEM INTO CHEWY PROTEIN GEL. 